You can try the fogger Jbest recommended.
Spray them heavily with Ortho's Systemic Bug killer.

The plants absorb it and the entire plant becomes toxic to the pests. In a bad infestation you may want to cover the soil and try dunking them in a soapy water bath and rinse first. Or spray them with a mix of 1/2 and 1/2 rubbing alcohol and water.

Use the systemic every other day for a week. You will be able to save the plants.

Ladygentian needs to be cautious about whatever she decides to use, making certain that it is safe for greenhouse use. The extra heat and humidity in a greenhouse can create real problems when some of these typical pest solutions are used.

That goes for the fogger, too. She'll need to make sure that it's the right kind of fogger and that it is designed for a greenhouse that is the size of hers. Foggers, when used incorrectly can cause damage to the plants, as well as the glazing material (unless it's glass).

tj

Rubbing alcohol is actually milder and less damaging than the dish detergents so often used by home gardeners, and most plants do very well with a misting of an alcohol solution for the welcome control of a wide variety of soft-bodied insect pests.

Alchohol killed every single leaf on my "Belmont Gardenia" and it was a weak soution, while my other type gardenias were not affected...Seemed as if this alchohol was absorbed through the leaves within a day in which the leaves turned a deep black, then the branches died back..So I would do a test on a leaf before ever spraying the whole plant with alchohol..

My mother lost her AV from spraying hers with alchohol.

But as Rhizzo said, most plants take well to a spray of it, such as all my citrus.

And the key is, not to do just one spray, but to keep a schedule of doing it until the little ones that hatch along the way are dead too..

By the way, "spraying" a plant with Alchohol does not kill scale. Been there done that...It is the oils, and sad to say, systemics that do the trick. I don't like sytemics, so I try to rub the ones off I see with a Q-tip and alchohol, and keep spraying with a week solution of neem and soap until they are gone..

About the alcohol and scale insects: it is very effective against the crawler stage of scale insects so useful for spraying along stems and under foliage. Not so much the adult scale.

Oils are still the most recommended solution for scale infestations...but also not particularly effective against the adults. Timing is important!

Just to further your point about adult scale, that is exactly what the owner of the local nursery told me today..

He said oils are the best defense against the adult stage..There are some very safe oils on the market to be able to be used indoors. Neem oil being one of them. He also recommended not using a systemic, which can be toxic in many ways indoors, although an easy way out. He himself would never use the systemic, and is amazed at how people come in there with children to buy it..Gross.

I hope you are safe, and your "olive tree" is looking good these days.

Mike:-)